From the post and comments:

"Futurama has been a show that probably showed me just how much talent is involved in voice acting. Two of my favorite tidbits that really helped me come to this conclusion were:

1: When we first see Morbo, Maurice LeMarche's voice was edited to sound that way but after he heard the edit he made the effect with his own voice and they never edited it in the studio after that.

2: Billy West is so excellent at changing voices that if there was scene where (for example) Fry, Zoidberg and the Professer were all talking he would read it all in order just like a conversation and just switch voices between lines when typically it would be done by reading all the lines from one character first and then doing the next one and so on

What are some of your favorite Futurama facts?? Does not have to be voice related."

"In Love's Labors Lost in Space Billy West did the distorted sound for the voice of M-5438 without editing. They kept stopping the session because they thought there was something wrong with the mics until they realized it was just Billy."

"Billy West voiced the two halves of Glurmo from the Slurm Factory without any kind of electronic modification. They demonstrated it in one of the commentaries- they had West just ad lib something in ½Glurmo's voice. I'm impressed."

"I honestly love Katy Segal's voice acting. She doesn't do anything to actually change her voice but when I hear it, I don't see Peggy or Katie I completely see Leela. She has this very sensual voice that sounds youthful and in command at the same time. She's just a damn good actress.

My favorite is in The Late Phillip J Fry when she kicks the TV with her typical hi-ya and ends it in a typical Leela cry."